Sampling apparatus



March 20, 1962 J. l.. REUss ETAL 3,025,707

SAMPLING APPARATUS Filed Feb. 19, 1958 FlEil United States Patent O 3,025,707 SAMPLING APPARATUS John L. Reuss, Lakeland, and Benjamin P. Bell, Mulberry, Fla., assgnors to International Minerals & Chemical Corporation, a corporation of New York Filed Feb. 19, 1958, Ser. No. 716,205 2 Claims. (Cl. 73421) The present invention relates generally to a sampling apparatus and more particularly to an apparatus for preparing a dry sample from a slurry stream.

In many processing operations, slurry streams, i.e., liuid streams containing liquid having iinely divided solids mixed therewith, are encountered. For example, in petroleum processing operations, a slurry stream containing heavy petroleum oil and finely divided catalyst held in suspension in the oil is frequently encountered. In various mining operations ores are transponted as a slurry, that is, the ore in nel-y divided form is mixed with water to form a slurry and the slurry is pumped to the ore processing plant. In many phosphate beneciation processes, various process streams, recycle streams, product streams. waste streams, etc. are slurries. For example, in Florida pebble phosphate mining operations, the mined phosphate is slurried with water and pumped to the phosphate processing plant. The tails or waste streams from the phosphate plant are also pumped as slurries to the waste disposal areas.

It is frequently desirable and oftentimes necessary to know the composition of slurry streams. It may be desirable to know the ratio of the liquid to the solids and in some instances it may be desirable to know the composition of the solid material. An example of this would be in a phosphate processing plant wherein the waste products or tails are dumped into a waste disposal area. It is desirable to know the phosphate concentration in the so-ca'lled tails, which are composed predominantly of silica, so that it can be determined whether or not an economical phosphate recovery operation is being effected. In the even-t that the phosphate concentration in the tails going to waste is high, this would indicate an inefficient operation.

The sampling of slurry streams is, however, very difiicult in that the slurries are usually transported through rather large pipes and the distribution of the solids through the slurry stream is not entirely uniform. Further, the slurry is, of course, a mixture of liquid and solids, and it often is necessary to determine the composition of only the solids, in which case it is necessary to `dry the solids.

Many continuous and semi-continuous analyzers for determining the concentration of one or more constituents in a mixture have been developed. Frequently, however, it is necessary to feed a predetermined dry weight of sample into the analyzer in order that the sample may be accurately analyzed. In such instances, it is necessary that the sampling device withdraw a representative slurry sample from the slurry stream, dry the sample (that is, remove the Water or other liquid), and then presen-t the dried sample to the analyzer in such a condition that an accurate determination can readily lbe made. Since most analyzers require that a predetermined weight of sample be fed to the analyzer, it is desirable that the sample be in a more or less tinely divided form so that an accurate weight of sample may easily be obtained. The present invention is concerned with the problem of withdrawing a slurry sample which is representative of the slurry stream, drying the slurry, and producing the dried particles in a finely divided condition so that they may be introduced to an analyzer of the continuous or sernicontinuous type.

It is an object of the present invention to provide a sampling apparatus.

It is another object of lthe present invention to provide a sampling apparatus for preparing a dry sample from a slurry stream.

It is a further object of the present invention to provide a sampling apparatus which will periodically withdraw a representative sample from a slurry stream, dry the slurry sample, and place the dried sample in a condition so that it may be readily introduced into an analyzing device of the continuous or semi-continuous type.

Further objects and advantages of the present invention will be apparent from the following description and the accompanying drawings which illustrate one form of the invention.

In the drawings:

FIGURE l is a side elevational view, partly in sec-tion, of a sampling apparatus embodying various features of this invention;

FIGURE Q is an enlarged sectional View taken along line 2--2 of FIGURE l; and

FIGURE 3 is a sectional view taken along line 3--3 of FIGURE 2, illustrating the crushing of particle clusters by the rollers.

The present invention provides an apparatus for withdrawing a representative sam-ple from a slurry stream, drying the sample, and reducing the size of the particles in the dried sample so that the dry material may be directly introduced to an analyzing apparatus of the continuous or semi-continuous type.

The apparatus of the present invention provides for introducing a slurry stream into a lower portion of a mixing vessel, and withdrawing a slurry stream from an upper portion of the mixing vessel. A sample of slurry is withdrawn from the mixing vessel at a central portion of the mixing vessel.

'The apparatus provides for introducing the withdrawn sample through a conduit onto a vibrating flat table-like member which is vibrated so as to agitate the slurry dropped thereon. The iiat table-like member is elongated and inclined 'downwardly from the place where'the slurry is initially introduced thereon. A heating means is positioned on the underside of the table-like member so that the table-like member may be maintained at a relatively high temperature to rapidly evaporate substantially all the water from the sample. 'Ille sample of material is rapidly dried by contact with the hot vibrating table-like member and continues down the inclined table-like member where the dry material is contacted by rollers. The material passes under these rollers and is reduced to a relatively small particle size. Upon reaching the lower end of the inclined table-like member, the dried material is in a relatively neiy divided form and may be dropped directly into an analyzing apparatus.

The use of this apparatus makes possible the sampling of slurry streams with a minimum of difficulty.

An embodiment of the apparatus of the present invention is shown in the drawings and is described in the following paragraphs. While the sampling apparatus shown in the drawings is specifically adapted for the sampling of a slurry stream containing silica and phosphorus values, it will be understood that the apparatus may be used in the sampling of other slurry streams with equal facility.

As will hereinafter become apparent, the sampling apparatus shown in the drawings includes, generally, a mixing tank 11, an elongated table-like member or pan i3, a vibrator 15 for Vibrating the pan 13, and heating means 17 which heat the pan @13 so as to volatilize liquid from a slurry sample dropped onto the pan.

Referring now more particularly to the drawings, the specitic sampling apparatus illustrated embodies various of the features of the invention, and, as has been pointed out, is particularly adapted to the sampling of a slurry o .9 stream containing silica and phosphorus values. The illustrated apparatus includes a frame 19 of fabricated construction having a series of suitable support legs 21, which support the mixing tank 11.

The mixing tank 11 illustrated in the drawings is a cylindrical tank having an open top. The mixing chamber or mixing tank 11 has an inlet conduit 23 connected at a lower portion of the mixing tank 11 for introducing slurry into a lower portion of the tank 1l. An outlet conduit 25 the tank 11 for conducting slurry out of the tank at an up- Ti'le diameter of the mixing tank 1s considerably greater than the diameter of the inlet outlet conduit 25. As the slurry enters the mixing tank 1v1, there is a decrease in velocity of the slurry stream, and due to the decrease in velocity there is a tendency for articles to settle out of the slurry to the bottom of the mixing tank 11. In order to prevent settling of the solid particles in the slurry and to insure substantially complete uniformity of the slurry within the mixing tank 11 an agitation or mixing means 27 is provided. The agitation means 27 includes a pair of spaced mixing blades 2f drivingly connected to a vertical shaft 31 which is driven at high speed by a high speed electric motor 33. The motor 33 is positioned above the tank so that the vertical shaft depends directly therefrom into the mixing tank 11. The lower mixing blade 29 is positioned slightly above the bottom of the tank 11 so as to maintain substantial agitation at the bottom of the tank.

The agitation means 27 keeps the slurry substantially uniform throughout the mixing tank 11. A sample taken substantially near the center of the mixing tank 11 is, therefore, representative of the material in the mixing tank at any particular instant of time. A means 35 is provided for withdrawing a slurry sample substantially near the center of the tank 11. The means 35 includes a conduit 37 which extends through the bottom of the mixing tank 11. The upper end of the conduit 37 terminates intermediate the top and bottom and sides of the tank 11 and somewhat adjacent the geometrical center of the mixing tank 11. The lower end of the conduit 37 extends somewhat below the bottom of the mixing tank 11. To control the flow of slurry through the conduit 37, a valve means 36 is provided. The valve means 36 is provided adjacent the inilow end of the conduit 37. It has been found that such an arrangement provides for the withdrawing of a representative sample of the slurry since no dead settling space is provided in the conduit 37. The valve means 36 may be operated by a suitable timing device (not illustrated) so as to open and close at predetermined intervals.

In the valve means 36 illustrated, the upper end of the conduit 37 is provided with a rubber valve seat 3S which is adapted to receive a valve plug 39. When the valve plug 39 is placed on the seat 3S the flow of slurry through the conduit 37 is stopped. The valve plug 39 is connected to a valve stem `41 which is movable vertically up or down by a suitable means, such as electrical solenoid means 43. The solenoid means e3 is connected to a source of electricity (not shown) which periodically activates the solenoid. When the solenoid 43 is not activated the valve plug 39 is seated on the seat 3S on the upper end of the conduit 37 thereby preventing ilcw of slurry through the conduit. Periodically, the solenoid 43 is activated for a predetermined time so that the valve shaft 41 is moved upwardly thereby unseating the valve plug 39 from the seat 38 on the upper end of the conduit 37 thereby permitting a predetermined amount of slurry material to -ilow downwardly through the conduit 37. In a commercial embodiment of the present invention the solenoid unseated the valve plug every four minutes and permitted 40 grams of slurry to flow downwardly through the conduit 37 before the valve plug was again seated.

The predetermined amount of sample slurry passing through the conduit 37 drops onto one end of the vibrating table-like member or pan 13. The vibrating pan 13 has a substantially flat bottom 45 (FIG. 2) and upwardly extending sides 47 for preventing the slurry material from spilling outwardly over the sides. The pan 13 is inclined downwardly in the direction of its long dimension so that the material fed to the uppermost portion of the pan will gradually move downwardly along the inclined bottom of the pan. The upper edges of the sides 47 of the pan are rolled over as indicated at 49 to present a smooth rounded upper edge instead of a sharp edge.

Near the left end of the vibrating pan 13 (FIG. l), and substantially under the portion of the pan that the sample of slurry is dropped onto, a vibrating means 51 is positioned. The pan 13 may sit on the vibrator 51 or may be rigidly connected thereto. The vibrator is of a high frequency type which vibrates the pan 13 at a high frequency. The slurry sample dropped out to the vibrating pan 13 through conduit 37 is therefore vibrated at a high frequency which tends to spread the slurry-uniformly over the bottom of the upper section of the pan.

In order to evaporate the water or other liquid from the slurry sample the heating means 17 is provided. The heating means 17 illustrated includes a pair of llat elongated heating elements 53 `which are connected to the underside of pan 13 along the left half (FIG. l) thereof and a pair of at elongated heating elements 55 Which are connected to the underside of the pan along the right half (FIG. 2) thereof. These heating elements are of the electrical resistance type and are connected to a source of electricity (not shown). The heat provided by the heating means 17 evaporates substantially all of the volatile liquid from the slurry sample and produces dry solid particles.

The vibrating pan 13 and heating means 17 tend to keep the solid particles dry and uniformly distributed over the bottom of the pan as the material moves downwardly along the inclined pan. There is, however, some tendency for particle clusters or agglomerates to form. Near the midsection and at the lower section of the 13 there are, therefore, provided rollers 57 and 59 under which the dry material must pass as it moves downwardly along the inclined pan 13.

The rollers 57 and 59 illustrated in the drawingare free rollers, that is, they are not driven; however, it 1s within the scope of the present invention to use driven rollers. In has, however, been found that an entirely satisfactory product is obtainable using free rollers as illustrated. Since the pan 13 is inclined there would be a tendency for the rollers 57 and 59 to roll down the 1ncline and to prevent this a pair of projecting pins 61 and 63 are provided. These pins project upwardly above the bottom of the trough and retain the rollers 57 and 59 so that their longitudinal axis is substantially perpendicular to the direction of movement of the dried particles down the pan 13. The rollers 57 and 59 illustrated are short sections of tubing or pipe; however, solid rollers may also be used. Further, the rollers 57 and 59` illustrated in the drawings are not mounted on any shaft; however, the rollers may be mounted on a shaft which is suitably secured within the sides 47 of the trough 13 so thatr the retaining pins 61 and 63 would not be necessary.

In the operation of the machine, the slurry is passed at a high rate through the inlet conduit 23 into the mixing tank 1v1 and exits through the outlet conduit 25. The mixing means 27 maintains the slurry within the mixing tank 11 is a high state of agitation. solenoid 43 is actuated and lifts the plug 39 off of the valve seat 38 and thereby permits a sample of the slurry to pass downwardly through the conduit 37 onto the upper end of the inclined vibrating pan 13. The vibrating inclined pan 13 is maintained at a relatively high tern- Periodically, the

perature by the heating elements 53 and 55 and therefore, almost immediately upon touching the vibrating pan 13, the water in the slurry is evaporated and the dried particles begin to descend down the inclined pan due to gravitational forces. The vibrating of the pan 13 also obviously aids in maintaining the movement of the dried particles down the inclined trough 13. As the particles pass downwardly on the vibrating pan 13 any particle clusters or agglomerates must pass under the rollers 57 and 59 and as the material passes thereunder, the vibration of the pan and the action of the rollers tend to break up the particle clusters and agglomerates. The dried particles leaving the ultimate end 65 of the inclined pan 13 are substantially dry and in a relatively subdivided state so that they are suitable for introduction to a sampling apparatus.

In one commercial embodiment of the apparatus which has been described, it has been possible to dry approximately 40 grams of a 50% solid slurry every 4 minutes. The present invention has been described with reference to a speciic illustrated embodiment of the present invention, however, other physical embodiments and various modilications Within the scope of the present invention will be obvious to those skilled in the art.

Various features of the invention which are believed to be novel are set forth in the appended claims.

We claim:

1. A sampling apparatus for preparing a substantially dry sample of material from a slurry stream comprising a tank, an inlet conduit connected to said tank at a lower portion thereof for delivering slurry into a lower portion of said tank and an outlet conduit connected to said tank at an upper portion thereof for removing slurry from an upper portion of said tank, a slurry sample removal conduit extending through said tank for removing a sample of slurry from said tank, said sample removal conduit having the inlet end thereof positioned intermediate the top and bottom and sides of said tank and having a valve means positioned adjacent the inlet end thereof, means for periodically opening and closing said valve means, said means holding said valve means in closed position for a predetermined time interval and in open position for a predetermined time interval to permit a v predetermined amount of slurry to be withdrawn from said tank through said sample removal conduit, a mixing means for mixing the slurry Within said tank, an inclined pan positioned so that the slurry sample passing out of said sample removal conduit is delivered onto said pan, a heating means on said pan for substantially immediately evaporating volatile liquid from the sluurry sample delivered onto said pan to thereby provide a substantially dry sample, and a vibrating means connected to said pan for vibrating said pan.

2. A sampling apparatus for preparing a substantially dry sample of material from a slurry stream comprising an open top tank, an inlet conduit connected to said tank at a lower portion thereof for delivering slurry into a lower portion of said tank and an outlet conduit connected to said tank at an upper portion thereof for removing slurry from an upper portion of said tank, a slurry sample removal `conduit extending through said tank for removing a sample of slurry from said tank, said sample removal conduit having the inlet end thereof positioned intermediate the top and bottom and sides of said tank and having a valve means positioned adjacent the inlet end thereof, means for periodically opening and closing said valve means, said means holding said valve means in closed position for a predetermined time interval and in open position for a predetermined time interval to permit a-predetermined amount of slurry to be Withdrawn from said tank through said sample removal conduit, a mixing means for mixing the slurry Within said tank, an inclined pan positioned so that the slurry sample passing out of said sample removal conduit is delivered onto said pan, a heating means on said pan for substantially immediately evaporating volatile liquid from the slurry sample delivered onto said pan to thereby provide a substantially dry sample, a vibrating means connected to said pan for vibrating said pan, and a roller positioned on said pan so that dry material passing down said pan passes under said roller whereby particle clusters and agglomerates are reduced in size.

References Cited in the le of this patent UNITED STATES PATENTS 217,053 Brooke July 1, 1879 1,341,898 Gendar June l, 1920 2,266,586 Braunen Dec. 16, 1941 2,516,097 Woodham et al. July 18, 1950 

